Machine for the manufacture of blades for turbojet engines



Dec. 9, 1952 P. J. REMY I MACHINE FOR THE MANUFACTURE OF BLADES FOR TURBOJET ENGINES 2 Sl-lEETS-SHEET 1 Filed Ndv. 27, 1951 m mm mm S H c O a w L a x.

Dec. 9, 1952 P. J. L. REMY 2,620,601

- MACHINE FOR THE MANUFACTURE OF BLADES FOR TURBOJET ENGINES Filed Nov. 27, 1951 2 SHEETS-SHEET 2 3 w 5mm 9 0ml HXBQA. \DTkQ c1 5 Patented Dec. 9, 1952 UNITED STATES PAT-TENT. JOVFFICE MACHINE FO-R THE MANUFACTURE OF BLADES FOR- TURBOJET ENGINES Pa'ul Joseph Lon "Rmy, lssy-les-Moulineaux,

"France, assignor' to Societe'des Ateliers de Mecanique "et-de Pyrotechnic S.M; P. ,-'Pa'ris, France,-a-joint-stdck company of France Application-November 2'7, 1951 Serial No. 258,468

.. In France. September 29, 1951 The present invention relates to armethod' and a machine for the machining by rotation of long, fiat and thin elements and; more particularly; for the production of turbo-jet reactor blades.

"Itis known that if the manufacture of the base of the bladeser'ving to anchor the latter offers no special di'iiiculty'; it is'quite the opposite as regards the production of the" blade proper which, in the actual state of the art, set'sproblem's 1 Claim. (Cl. 51- 101) This method involves a huge consumption; of

dies that are very costly due tothe time taken to produce them and to the considerable number of copying machines required to ensure their manufacture. 'Itrequires, furthermore, minute care during the dieing operation itself.

In addition, the-blades cannotbe completely fihishedby this operation and the trailing and leading edges must be machined.

that are particularlycomplicated tosolve. "Finally," the accuracyof the profiles can only "'Up to the; present, the methods'which have be approached to within a few tenths of amilli been tried or c'onsideredle'ad to a hold'up inthe metre for .massproduction. manufacture of the said elements, said hold up (6) By mechanical machining. This method, originating either from thedifiiculties ofmanuwhich is the only one employed originally and facture initselfor from the greatconsumption' isstill beingused now for prototypes, has been of tools "serving for the manufacture of the blades. discarded for mass production in view of machin- These dii ferent methods, used or beingconin difiiculties' and theenormo'usmeans which sidered at'the present time," are the'following: must bebroughtintoplay to keep up with the "(D y moulding, 'w h' oSt'WaXaS" rates of manufacture necessary for the. equipdental P s, or with frozen mercury. ment of a modern air power in turbo-jet engines.

The main drawback of this'methodisthe lack The 'difficulties which necessitated giving up of mechanical homogeneity f e elementsthis"'method originate fromthe little rigidity A very strict supervision'in Production f offered by'theblade when the pressure of the themetalandin the castingdoes'not in fact ext i exerted perpendicularly to the faces of cludein'clusions and flaws which-may'causerupthewblade, that is'to say in the direction of its ture. smallest thickness.

F y; th m n w ou ht and t er It has. indeed been attempted to give more fore nbt fibered, it will never possess the chai r'igidity to the blade by machining it directly'in acteristics'ofresistance "of the metal subjected block having"the' ti of t 'b of th to the said treatment. blade and by therefore trying to obtain directly (2) By sinterin f ll wi g a method of m thezpr'ofilein a singlepass, the blade being solidly facture-identical with-that of tungsten carbides. fixed by" its base in the mounting. But it is The said method which is m ooonomical'than obvious that the length of the blade, relative to the previous has the same" disadvantag as the section of the block, is such that 'it cannot regards resistance. be prevented from vibratingunder the strain of (3) By stampi g and p g'o aIhOHOW ad the tool, even by supporting it by meansof a either y means of two shaped andw'elded half tail-"stock on the opposite side ttofits attachment sheet-metal shells, this solution coming up t th hine, I against v ry complica weldinaproblems This method moreover requires considerable to the lack of'homogen'eity and'the deformations 4 work on the p r f the 15001 (1116 to thogreat caused by the W l n r stampinawhich thicknesses which have beenleft toimprovethe allows of producing the blade w o w l rigidity, and the result isran abnormally. rapid this solution offering however such difficulties Wear of t t a very great, slowness'offihe that: ai embodiment S'P OY d r the work and, consequently, lowproduction; 'vi bramoment unreaiizable. tion's shownon the element by an appreciable (4) By vrolling by means of a d e roughness of the whole surface which takes much i p e d of a ufa'oture of knife time to polish; diiferences in the accuracy of the blades, said'blades in' their general lines being profiles; exaggerated consumptionof very costly relatedto profiledblades. metal, in view of the extra thicknesses to be Howeverysince the leading and trailing edge 0 m ed, I I i cannot befinishedby rollin they would r qu r One of the objects of my invention'is a'nithod substantial machining -in orderto finishfthe anowingstamped turboajet-blad to a m same. 7 V A 1 by means ofa grindstone withonly the normal "(5) *By' forging, theelement beingproduced by extra thicknesses-necessary for conventional diedieing to flnisheddimension's. ing, that is to say of the order of 1 to 2 mm.

Another object of my invention is to provide a method of machining turbo-jet blades by which the loss of high cost metal is reduced to an admissible percentage.

Another object of my invention is to provide a method which imparts to the blade, during the machining of its profile, a rigidity such that the drawbacks of the above mentioned present-day methods are eliminated.

Another object of my invention is to provide a machine for the machining of turbo-jet blades and for putting the above method into practice.

Other objects of my invention will become apparent from the following description, with reference to the accompanying drawing, in which:

Fig. 1 is a general diagram of the method according to my invention:

Fig. 2 is a perspective view of a, machine for machining turbo-jet blades, carrying out the method according to my invention.

The method according to my invention is fundamentally characterized by the following points:

(1) The element to be machined I (see Fig. l) is rigidly secured by its two ends Ia and lb to co-axial driving chucks 2a and 2b of any suitable type capable, on the one hand, of ensuring the rotation of the element and, on the other hand, of submitting the same to considerable traction during machining.

(2) The chucks 2a and 2b are rotated in the same direction and strictly at the same speed. To this end, the chucks are interconnected by means of a positive kinematic chain which I have shown diagrammatically in Fig. 1 as composed of gear train lfla, lb, I la, l lb, the first two gears being secured to the spindles 3a, 3b carrying the chucks and the two others to a shaft l2 rotated by a motor l6, through the medium of a pinion l5 and a toothed wheel l4.

(3) The securing chucks 2a, 2b for the blade I are provided with a device which enables the blade to be subjected to considerable traction, during its machining by a grindstone I1. I have shown this traction device diagrammatically as composed of a plate I rigid with the pin 3a of the chuck 2a and on which bears the end roller of a lever B which is hinged to an intermediary point 8a, the other end of which is subjected to the action of a cylinder and piston control device 9.

A reproducing member of any conventional type, which will be described in detail hereafter, controls the relative displacement between the element to be machined I and the grindstone l! in response to the relative displacement between a feeler roller and a master form.

The method according to my invention offers the following fundamental advantages:

(a) The blade, being rigidly embedded by its ends in its chucks possesses, due to this, a resistance to bending four times greater than that which it would have if it were embedded at one end only.

(b) The blade, being rotated at its two ends through the agency of the two driving chucks, has a much smaller torsional deformation, under the pressure of the tool, than the one it would have if it were only driven at one end.

(c) The rigidity of the blade is yet considerably increased due to the fact that it is machined under traction.

Fig. 2 shows a practical embodiment of a machine for machining turbo-jet blades, carrying out the described method according to my invention.

This machine comprises a base 6 in which may slide at right angles, on the one hand, the slideblock 2l of a carriage supporting the grindstonecarrying frame 22 and, on the other hand, the slide-block 23 of the movable copying table 24.

On the copying table are arrangedthe securing chucks, the positive kinematic chain, the device for tensioning the element to be machined as well as the above mentioned master form.

The turbo-jet blade I to be machined is secured by its two ends Ia and lb in the anchoring chucks 2a and 2b the respective spindles 3a and 3b of which are mounted in coaxial bearings 4a and 4b integral with a housing 25 secured to the table 24.

The positive kinematic chain is formed, in the example shown, of trains of pinions and endless screws, such as Illa, Ila which may be seen in the cut-away portion of Fig. 2, connected by shafts 26a and 26b to a second train of pinions and endless screws 21a and 21b. The latter are, in their turn, connected to the driving motor I6 rigid with the table 24, through the medium of the respective shafts In and l2b. This positive kinematic chain, while allowing the chucks 2a and 2b to be rotated in the same direction and strictly at the same speed, furthermore enables the relative fixing angle of the driving chucks to be controlled at will.

In the housing 25 are arranged the various parts of which the tensioning device is composed, including the lever 8 hinged at 8a, one end of which comprises a roller bearing on a stop I rigid with the spindle 3a for the chuck 2a and the other end of which is subjected to the action of the cylinder and piston control device 9.

At the end of the shaft 26a is mounted a bevel,

gear 28 driving a shaft 29 serving to rotate the master form 30.

On the grindstone-bearing frame 22 are arranged:

(l) The grindstone proper l1;

(2) A unit for truing the grindstone and including: a diamond 3| mounted on a diamondcarrying carriage 32, itself mounted on a diving carriage 33; a control spindle 34 for the rack of the diamond-carrying carriage; a spindle 35 for driving the diving carriage for the diamond car-' rier.

(3) A slide-block 36 in which may slide a carriage 31 supporting the drum 38 carrying feeler rollers 39.

The operation for profiling the blade I may advantageously be carried out in two successive cutting strokes, viz.:

(1) A blank cutting stroke to or mm. from the finished dimension;

(2) A finishing cutting stroke of 2 to mm., after truing of the grindstone to the diameter corresponding to that of the reproducing feeler roller 39.

The amount by which the grindstone is trued is advantageously determined in an experimental manner once for all in function of its wear, the diameter of the reproducing rollers being deducted therefrom. Hence, these rollers may be arranged on a revolving drum offering to the feeler the roller corresponding to the diameter of the grindstone, in accordance and progressively with its wear truing operations, until the grindstone is completely used up.

Having shown and described an embodiment of my invention, it is obvious that changes and modifications may be made thereto within the limits of the principle of my invention and within the scope of the accompanying claim.

I claim:

Machine for machining by rotation long, flat and thin parts and, more particularly, turbo-jet blades, the said machine including in combination a copying table, movable relative to the base of the machining and on which are arranged: two securing and rotating devices for the blade to be machined, having a common rotation axis, a motor, gear trains connecting the said motor to the said securing devices for rotating them in the same direction and strictly at the same speed, an adjustable control mechanism for increasing the spacing between the said securing devices and subjecting the blade to be machined to considerable tension during machining, a master form, a gear train connected to the said motor for rotating the said master form; a tool carrying carriage movable relative to the said movable copy- 6 ing table a rotative tool mounted on the said tool-carrying carriage and in contact with the blade to be machined, a feeler roller carrying carriage movable relative to the said tool-carrying carriage, and feeler rollers mounted in a revolving drum on the said roller-carrying carriage and placed selectively in contact with the said master form. r

PAUL JOSEPH LEON REMY.

REFERENCES CITED The following references are of record in the file of this patent: V

UNITED STATES PATENTS Number Name Date 1,755,937 Steiner Apr. 22, 1930 2,102,505 Berthiez Dec. 14, 1937 2,527,285 Whitehead et a1. Oct. 24, 1950 2,531,921 Schultz Nov, 28, 1950 

